Projects for 2012

Seabed Observations

Biology in Puget Sound

Estuarine Circulation

Chemical Tracers



This year we will be
cruising aboard the
R/V Clifford Barnes.

SEABED OBSERVATIONS

As discussed in class, Whidbey Basin is the primary sink for sediments delivered to Puget Sound by the Skagit, Snohomish, and Stillaguamish Rivers. Therefore, projects concerning the fate of sediments from these rivers (and/or comparisons between them) would be appropriate.

The primary tools that we will have available to us for sedimentary geology on the Barnes this year, in addition to the standard set of hydrographic parameters captured by the CTD, are grab samples and ‘box’ cores (ca. 60 cm long). As much as possible, we will subsample the cores while at sea. All samples and unprocessed cores can be brought back to the lab for analysis of grain size, as well as various radioactive isotopes that can be used as tracers of sediment origin, accumulation rate or bioturbation.  Box cores can be used to look at sediment textural (grain size distribution) and isotopic changes with depth, and can be x-rayed in order to analyze layering.  Much of the sediment in Saratoga Passage is heavily bioturbated (stirred up and burrowed biological activity), so layering may be less informative than other techniques. 

There are many possible research questions one might ask, but we are severely limited by time in this course. For this reason, we will limit ourselves to basic observations of sediment texture and/or accumulation rate among the various stations that we occupy in Saratoga Passage and Port Susan. In particular, students might choose to study:

  • Particle fluxes through the water column – A combination of suspended sediment concentrations (from turbidity sensor on the CTD) can be merged with water velocities (from ADCP) to evaluate fluxes at different locations in Puget Sound.
  • Sediment grain size and benthos – Seabed material recovered by box cores and grab samples can be used to evaluate the distribution of sediment size, and possibly its relationship to large benthic organisms (if sampled).  Other valuable relationships are proximity to river sources, which are important for Puget Sound.
  • Sedimentary structure related to physical/biological processes – X-radiographs of box and kasten cores can be used to document the impacts of waves and currents and subsequent bioturbation on the formation sedimentary deposits around Puget Sound.
  • Sediment deposition and accumulation rates – A range of short-lived natural radioisotopes can be used to document short-term deposition (e.g., river flood) or longer-term accumulation rates (e.g., over the past century).  This involves measurements of vertical radioisotope profiles in sediment cores.